Purine-rich foods can cause high uric acid in the blood because uric acid is a product of purine breakdown. To avoid the complications of high blood levels of uric acid such as gout, kidney stones and kidney dysfunction, be careful about the amount of purine-rich foods in your diet, especially if you are susceptible to one of the above conditions.
Uric acid is the breakdown product of purine degradation. Purines are components of DNA. In the human body, uric acid is present in an ionised form called urate primarily in the blood plasma and fluid around joints (called synovial fluid). Urate is produced primarily in the liver and small intestines. The majority of urate is excreted in the urine and the rest in the faeces.
Abnormal uric acid levels
High uric acid in the blood (called hyperuricaemia) is the result of increased production, as in tumour lysis syndrome, or decreased excretion of the substance, as occurs in kidney disease. Hyperuricaemia can cause some to develop gouty arthritis, kidney stones or kidney dysfunction. Low levels of uric acid in the blood (hypouricaemia) is caused by decreased production or increased excretion. However, hypouricaemia is not associated with any clinical problems and generally does not require any treatment.
The diet contributes to blood urate levels through purine-rich foods. According to Dr. Clifton Bingham III of Johns Hopkins Arthritis Centre in the U.S., purine-rich foods include herring, mussels, yeast, smelt, sardines and sweetbreads, anchovies, grouse, mutton, veal, heart, bacon, liver, salmon, turkey, kidneys, partridge, trout, goose, haddock, pheasant and scallops.
Complications of hyperuricemia
According to "Harrison's Principles of Internal Medicine", the most well-known complication of hyperuricaemia is gouty arthritis, which occurs because of deposition of urate crystals in the joints.
Additionally, hyperuricaemia is associated with formation of kidney stones because the high urate precipitates into crystals in the urine. This can lead to urate stones or serve as a starting point for crystallisation of other types of stones such as calcium oxalate or calcium phosphate.
Last, hyperuricaemia can lead to kidney dysfunction. This occurs because of deposition of urate crystals in the kidney, causing an inflammatory reaction. This may lead to acute kidney failure.
Pharmacologic treatment of hyperuricaemia
The main pharmacologic agent used for hyperuricaemia is allopurinol. It blocks the enzyme that produces urate during purine degradation. It is used in patients with gout and to prevent tumour lysis syndrome in those with haematologic cancers.